一种实用快速的车牌字符分割方法

针对车牌自动识别系统中的字符分割问题,提出了一种基于车牌字符几何特征的分割字符算法。该方法先用数学形态学对二值化后的车牌图像进行一系列的形态运算,去除掉一些无用信息,使得字符与车牌左右边框、字符与字符之间空懈变大,便于划出字符间的垂直分割线,然后使用一种新的快速测量车牌倾斜度的方法进行校正。实验结果表明,该算法原理简单实用,分割速度快,分割的质量好,便于下一步的识别。     

裸体方格星虫体壁形态和组织学结构

报道了裸体方格星虫体壁的形态和组织学结构.结果表明:裸体方格星虫体壁由吻和躯干两部分组成,吻长与躯干长之比介于0.3与0.4之间,体壁由外到内依次由角质层、上皮、结缔组织层、环肌层、纵肌层和壁体腔膜组成.角质层是由上皮细胞分泌而成的非细胞结构,主要分布于躯干体壁;上皮薄,为单层柱状上皮;肌肉发达,外环内纵,均成束状分布;体壁的最内为壁体腔膜,由单层上皮细胞组成,朝体腔侧有具纤毛细胞的存在.AB-PAS染色显示体壁具有2种类型的粘液细胞,主要分布于吻部体壁上皮,躯干体壁上皮仅有少量的酸性粘液细胞存在.     

基于空间句法的郑州城市形态演变研究

空间句法在城市形态量化研究中具有独特的优越性,通过对句法轴线整合度、整合度核心和智能度等参数值的定量分析,总结出城市形态发展及演变的特征,准确判定城市空间拓展方向,从而为城市建设发展方向提供参考依据．运用空间句法,对郑州城市空间形态特征和演变过程进行研究,结果表明：1930---2012年,郑州城市形态由方格网状逐步向环网结合组团模式发展;城市形态演变表现出明显的历史依赖路径;在拓展方向上,城市中心一直集中于主城区,并向东、西、南方向扩展．     

钢-铝合金薄壁管压缩塑性连接成形性分析

以St16钢管和6061铝合金管为对象,分析了一种新的薄壁管塑性连接方法连接这2种金属薄壁管的可行性。基于Abaqus软件建立了压缩塑性连接仿真模型,设计了薄壁管塑性连接专用模具,通过实验对仿真模型进行了验证。重点讨论了压缩塑性连接过程中管坯的相对自由长度、模具与管坯间隙、芯棒与管坯间隙对成形性的影响规律。结果表明,基于压缩形成褶皱的塑性连接方法适合于异质金属薄壁管的连接;压缩塑性连接的关键技术在于正确设计管坯自由长度、管坯与芯棒、管坯与模具间隙量,使被连接两管在压缩失稳之后的塑性变形量和变形方向协调,确保内外褶皱的波形轮廓接触紧密。对研究的St16/AA6061薄壁管,管坯相对自由长度满足1.250g/r₀<1.625、模具与管坯外表面间隙为0.07～0.20倍的壁厚、芯棒与管坯间隙为0.07～0.27倍的壁厚是压缩塑性连接成功的前提条件。     

Highly mechanical and high-temperature properties of Cu–Cu joints using citrate-coated nanosized Ag paste in air

Today,a growing number of third-generation semiconductor-based power devices are used in products that can continuously operate at high temperatures for extended periods of time.Hence,traditional tin-lead and lead-free solders are no longer suitable for modern electronic packaging.A common method is to apply Ag paste for bare Cu-Cu joints under an inert or reductive atmosphere.In this study,the citrate-coated nanosized Ag paste was utilized to generate robust bare Cu-Cu joints under atmospheric ...     

Improving knowledge of the cyclorrhaphan larva (Diptera)

A significant factor in the evolution of the Cyclorrhapha (Diptera), the most biodiverse of higher dipteran taxa, is the larva. The larva also has wide-ranging trophic and environmental relationships, including positive and negative impacts on human health and wealth. Despite its importance, the larva is neglected and a low proportion of species are known in this stage. In this paper, factors contributing to larval neglect are reviewed, including: poor attitudes leading to cycles of neglect and shallow treatment; taxonomy that uses adult not larval stages; lack of material in collections; rearing barriers, and presumptions of morphological similarity suggesting that characters will be problematic to acquire and analyse. Neglect is pervasive and affects many subjects; those considered here are: species inventories and rarity assessments for biodiversity and conservation, in which larvae are usually ignored although they can be more cost-effective to sample and a richer source of environmental data; determining larval feeding modes where controversies due to conflicting evidence persist unresolved; and reliance on a limited pool of increasingly old publications whose data are repeated rather than tested and updated with new research. In an attempt to reinvigorate interest, which is the main aim of this paper, poorly assessed larval features possibly significant to cyclorrhaphan diversification are also considered. These include: change facilitated by independently evolvable modules; rapid change enabled by labile trophic morphology; shifts between saprophagy and phytophagy due to opportunities provided by angiosperm evolution; and enhanced adaptive potential resulting in derived more than basal taxa developing adaptations that enable access to new and little used resources. Apart from the need to rear more larvae, a major conclusion from this review is that knowledge will improve when the movement capabilities of larvae are used to inform morphological and taxonomic analyses.     

具有不同形貌的α-Fe_2O_3超细粒子可控制备

采用水热合成法,通过改变反应条件与表面活性剂的种类、添加量、铁源等,制备了具有不同形貌的Fe2O3超细粒子,并利用扫描电镜与X射线衍射仪等对Fe2O3粒子的形貌和尺寸及晶型结构进行了观察.研究表明:反应温度、反应时间、p H值和反应物添加量的比例等都会影响Fe2O3粒子的形貌和尺寸,通过调控添加剂种类等实验条件,获得了片状、立方体状、汉堡状、梭子状、长方体状、核桃状、六棱柱状、中空状等Fe2O3粒子的不同形貌,实现了对α-Fe2O3超细粒子形貌的可控制备.     

铝型材表面喷涂质量的图像检测与研究

针对用人眼检测铝型材表面喷涂质量效率低且容易疲劳的问题, 提出了基于数学形态学颗粒分析和改进后的模糊核聚类的图像检测方案。对铝型材表面喷涂的图像进行形态学颗粒分析, 利用数学形态学的并行结构特性通过核函数在特征空间中进行模糊核聚类, 从而达到质量检测的目的。实验结果表明, 该方法收敛速度达到18. 4 s, 分类准确率达到91. 6%, 在整体性能上超过传统的聚类方法, 并具有较强的鲁棒性。     

Bragg型声光双稳系统的稳态特性及非稳振荡

本文从理论上计算及分析了带有延时反馈回路的Bragg型声光双稳系统的双稳特性及非稳特性。由系统的动力学方程、稳态方程出发,给出了出现双稳态的参数范围。计算并绘出了非稳区域边界,分析了非稳振荡波形变化规律及其模结构。     

膨化真丝的形态结构研究

本文用扫描电子显微镜的方法研究了膨化真丝的表面形态及断面形态结构,直观地解释了真丝的染色渗透性及上染率随其膨化度增大而增加的现象;并观察到膨化真丝的原纤化现象和由此产生的真丝断面形态变化。